This invention relates to hyperbaric gas treatment devices and, more particularly, to devices which apply localized hyperbaric oxygen therapy to skin lesions.
The devices heretofore used in therapeutic topical hyperbaric oxygen treatment generally employ a sleeve-like oxygen chamber which receives and encloses a limb having a skin lesion or employ a cup-like oxygen chamber which is applied directly to the skin with its mouth circumscribing the lesion. Apart from its greater applicability to different parts of the body, the cup-like chamber in comparison with the sleeve-like chamber permits less exposure of unafflicted local areas of the patient's skin to pressurized treating gas, whereby its use involves less risk of pressure interference with capillary circulation in such local areas. However, significant risk in respect of such interference still remains as a result of design measures effected to take into account the widespread belief that a gas-tight seal should be provided between the skin and the mouth of the cup-like chamber.
For example, U.S. Pat. No. 4,224,941 granted Sept. 30, 1980 discloses a hyperbaric topical treatment device employing a flaccid oxygen bag which is rendered leak proof by bonding an annulus defining its mouth to a pad, so that a central opening in the pad registers with the mouth, the pad being adhered in gas-tight relation to the skin of the patient with the central opening cupped over the lesion in circumscribing relation. A hyperbaric oxygen atmosphere is then maintained in the bag, and exerts a force on the annulus which combines with the adhesive force between the pad and skin to doubly ensure against leakage from the inflated bag.
Another design measure consonant with the prior art belief that the gas-tight seal should be provided is illustrated in U.S. Pat. No. 4,328,799 granted May 11, 1982. There, a hyperbaric topical treatment device employs a rigid cup-like oxygen chamber which is rendered leak proof by forcefully maintaining a resilient sealing gasket at the mouth of the chamber against the skin of the patient so as to circumscribe the lesion.
The prior art belief has even been respected in designing non-hyperbaric topical treatment devices, as can be seen from U.S. Pat. No. 3,610,238 granted Oct. 8, 1971. There, a porous pad is encased by flexible sheet material adhered only to the opposed major surfaces of the pad so as to leave an annular oxygen channel surrounding the pad periphery, the pad having a central opening which extends through the sheet material at both major pad surfaces. The encased pad is either adhered or taped to the skin of a patient with the central opening mouth at the lower major pad surface cupped over and circumscribing the lesion in gas-tight sealing relation. Pressurized oxygen is fed to the peripheral oxygen channel for passage through the porous pad into the oxygen chamber formed by the central opening where the oxygen passes over the lesion and, being blocked by the gas-tight seal around the lesion, freely escapes from the unobstructed opening at the upper major pad surface, thereby to prevent atmospheric dust from settling on the lesion.
In each of the foregoing prior art disclosures, the design measures taken to provide a gas-tight seal at the lesion-circumscribing mouth of the oxygen chamber will cause pressure to be exerted on the local skin area which may interfere with capillary circulation and which, in view of the tenderness and sensitivity of such area, will at least be a source of unwelcome irritation.